I. Field of the Invention
The present invention relates to radio communications. More particularly, the present invention relates to wireless access to a local exchange carrier network.
II. Description of the Related Art
The availability of personal communication services (PCS) in the 1.9 GHz band is a growing segment of the wireless market. PCS is a boon to the holders of the bandwidth licenses. The wireline (local exchange carriers) and cellular operators, however, face losing subscribers because of this new technology.
The average subscriber is not likely to know or care about the subtle technology differences between cellular and PCS. It is generally expected that the cellular operators will retain the high-speed, high-mobility subscribers while the PCS operators are more likely to gain the low-speed, low-mobility subscribers.
The local exchange carriers (LECs) are at a severe disadvantage due to their extremely large and expensive telephony infrastructure that is mobility-incapable. Mobility has been shown to be of high value to customers even though, most of the time, they need only basic voice services.
There are currently a number of options that provide subscribers wireless access to wireline services. These options include wireless local loop, cellular/PCS overlay, and Generic-C. These technologies all provide some level of mobility but also have some limitations.
Wireless local loop, with the in-building equivalent Wireless Adjunct, are designed to replace the last few yards of copper wire to the subscriber's telephone with a radio link. Various wireless local loop solutions employ a variety of RF technologies, but their general characteristics are similar: they appear to the host LEC office as a set of subscriber lines and convert the signaling transmitted over the RF interface into the signaling required by the LEC and vice versa. A wireless local loop solution is little more than a protocol converter for wireless telephones.
The primary advantage of a wireless local loop is cost. An RF interface is often less expensive than a copper loop, especially in markets that do not have an extensive telecommunications infrastructure. However, wireless local loop solutions do not offer much in the way of subscriber mobility, other than that which is inherent in a radio link. Hand-off is not available nor is the ability to roam away from the home LEC office.
The cellular/PCS overlay is a well established technology that is widely available. The cellular/PCS overlay provides full wireless access and roaming capabilities throughout the LEC region. The cellular/PCS overlay is a cellular or PCS system (or network of systems) that covers the same geographic region as the LEC network. Wireless and wireline subscribers may freely call between these networks, but are served solely by their own network.
There are a number of drawbacks to the cellular/PCS overlay. The primary disadvantage is that the cellular/PCS network lacks service integration with the LEC network. The overlaid cellular or PCS network is entirely self-contained and separate from the LEC network. The only point of contact between the two networks is the tandem trunks connecting them. The operating company can offer full mobility and roaming as part of their business but cannot offer their wireline services to their wireless subscribers and vice versa.
Generic-C attempts to combine wireless local loop-like radio access with cellular or PCS-like networking. Unfortunately, the standard is still being defined and requires advanced telecommunication services, such as ISDN and advanced intelligent networking (AIN), to be deployed within the LEC network in order to function.
The average subscriber only needs wireless services within a city's boundaries or similar geographical area. For this type of subscriber, a cordless telephone is not powerful enough while full cellular service is too expensive. There is a resulting unforeseen need for a system that offers wireless access throughout an LEC's current switching and network infrastructure.